Commodity money consists of objects having value or use in themselves (intrinsic value) as well as their value in buying goods.
Representative money is an item such as a token or piece of paper that has no intrinsic value but can be exchanged
Fiat money is a government-issued currency that is not backed by a commodity such as gold. Fiat money gives central banks greater control over the economy because they can control how much money is printed. Most modern paper currencies, such as the U.S. dollar, are fiat currencies.
Medium of exchange is a term in economics referring to any item that is widely acceptable in exchange for goods and services.
Barter is exchange (goods or services) for other goods or services without using money.
Credit is a contractual agreement in which a borrower receives something of value now and agrees to repay the lender at some date in the future, generally with interest.